As a language teacher I can tell you that speaking "Spanglish" is actually an effort to integrate with the US. If someone hasn't had the long years if training necessary to learn to speak a foreign language fluently, but still does their best, I contend that that is wholly different from refusing to adapt to a regional variant of your own language. Spelling things the British way doesn't make you less American, as I believe I said before, but people do appreciate when immigrants make an effort to integrate. Personally, I feel that we have a responsibility to integrate; it doesn't mean we have to give up who we are, just that we should display a little flexibility, open-mindedness, and willingness to learn new ways.